Controllable Synthesis of Monodisperse Er3+-Doped Lanthanide Oxyfluorides Nanocrystals with Intense Mid-Infrared Emission

Abstract

Monodisperse lanthanide oxyfluorides LnOF (Ln = Gd, Y) with mid-infrared emissions were controllably synthesized via a mild co-precipitation route and a subsequent heat-treatment. The detailed composition and morphology were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and high resolution transmission electron microscopy (HRTEM). The results showed that monodisperse GdOF:Er3+ were nano-riced shape with length about 350 nm and width about 120 nm, while the quasi-spherical YOF:Er3+ were uniform nanocrystals with an average size around 100 nm. The influence of calcination temperature on the size and phase transition of LnOF nanocrystals was also investigated. The photoluminescence (PL) spectra indicated that the 2.7 μm emission of Er3+ had achieved in both GdOF and YOF nanocrystals, which were calcined at different temperatures. In addition, the decay time of both 4I13/2 and 4I13/2 energy levels corresponding to Er3+ in YOF nanocrystals were also studied in detail. The results suggested that both rice-shaped GdOF nanocrystals and YOF nanocrystals could provide suitable candidate materials for nanocrystals-glass composites, which could be a step forward to the realization of mid-infrared laser materials.

Novel YOF-Based Theranostic Agents with a Cascade Effect for NIR-II Fluorescence Imaging and Synergistic Starvation/Photodynamic Therapy of Orthotopic Gliomas

“…Therefore, the early diagnosis of malignant gliomas is particularly significant. Presently commonly used imaging methods for glioblastoma diagnosis mainly include positron emission tomography (PET), magnetic resonance imaging (MRI), single-photon-emission computed tomography (SPECT), and near-infrared (NIR) fluorescence imaging. , In recent years, NIR fluorescence imaging, especially in the second biological window (NIR-II FL), has been given much more consideration owing to its strengths of high sensitivity and spatiotemporal resolution, deep penetration, noninvasiveness, and low background noise. − Many kinds of probes have been explored as candidates for NIR-II FL in vivo until now, such as organic molecules, quantum dots, rare-earth fluorescent nanoparticles, and single-walled carbon nanotubes. − Among them, the rare-earth fluorescent nanoparticles are particularly fascinating owing to the exclusive optical properties, including large Stokes, narrow full width at half-maximum, and tunable excitation and emission, as well as good photostability. − Lanthanide oxyfluorides (LnOF, Ln = Y) nanocrystals with the characters of both fluorides and oxides (i.e., low phonon energy, good optical transparency, and chemical stability) exhibit good potential to act as promising probe for NIR-II FL. − Moreover, Nd 3+ ions with relatively large cross sections could serve as good sensitizer for efficient NIR-II emission excited by 808 nm laser through a self-sensitization process. , Therefore, the Nd 3+ -doped YOF fluorescent nanoparticles would be promising candidates for NIR-II FL of orthotopic glioma in vivo.…”

Highly thermostable fluoride nanocrystal-in-glass composites (NGCs) for mid-infrared emission

“…For example, the typical annealing process for the organic ligands removal usually brings phase transition or crystalline coarsening at high temperatures. 24,25 Thermal corrosion occurring between NCs and glass matrix also results in performance degradation during co-sintering. 26 Such undesired interaction proposes a high demand for the thermal/chemical stability of NCs.…”

Systematic Study on the Luminescent Properties, Thermal Stability, and Magnetic Behavior of GdOF: RE3+ (RE = Eu, Yb, and Er) Red Phosphors with Various Morphologies

“…Xu et al successfully synthesized GdOF:Yb 3+ , Er 3+ samples with different morphologies by changing the amounts of EDTA, but they showed similar emission color and intensity . He et al reported the synthesis of GdOF:Er 3+ and YOF:Er 3+ under different calcination temperatures and discussed the influence of calcination temperature on 2.7 μm emission of Er 3+ , and the sintering temperature effect on DC and UC luminescence deserves further investigation . Han et al prepared Gd 4 O 3 F 6 :Yb 3+ , Ho 3+ with different additives, which exhibited different morphologies.…”

“…34 He et al reported the synthesis of GdOF:Er 3+ and YOF:Er 3+ under different calcination temperatures and discussed the influence of calcination temperature on 2.7 μm emission of Er 3+ , and the sintering temperature effect on DC and UC luminescence deserves further investigation. 35 Han et al prepared Gd 4 O 3 F 6 :Yb 3+ , Ho 3+ with different additives, which exhibited different morphologies. The samples showed a similar spectral shape but distinct luminescence intensity, and some reasons were pointed out.…”